Signaling system



June 5, 1934. DOUGLAS 1,961,820

SIGNALING SYSTEM Filed Oct. 7. 1929 Fig.2

Inventor:

Nom/el Douglas,

BMW

His Attorneg.

' UNITED STATES PATENT OFFICE SIGNALING SYSTEM Norvel Douglas, Lawrence,Kans., assignor to General Electric Company, a corporation of New YorkApplication October 7; 1929, Serial No. 397,893

'7 Claims. (01. 179-171) My present invention relates t signaling sys-November 20, 1928, entitled Signal transmitting terms includingoscillation generators of the type I11eahSaIld Which is assigned to theSa assignee disclosed in copending application, Serial No. 389,- aS thepresent application, d t at W th a con- 067, filed August 23, 1929 by Elth stant value of field current the oscillations vary '5 entitl d Highfrequency magnetron apparatus, inversely as the anode potential througha cer- 60 and which is assigned to the same assignee as the tain rangethereof- I the manner presently present application. It has for itspurpose to probe described the anode potential y be Va vide meanswhereby oscillations produced by genin response to Signal Currents, Suchas these p eraters of th t e i i t may be modulated duced by amicrophone, or a like signal device,

1 10 in accordance with desired signals. and in this manner, modulationof the intensity 65 h novelfeatureswhichIb 1ie t b h of the oscillationsproduced in accordance with teristic of my invention are set forth withparticuthe Signal Currents may he eiheiently accomlarity in the appendedclaims. My invention it- P self, however, both as to its organizationand AS Shown in 1 this result is at a ned by "'15 method of operation,together with further obmeal-1S of an electron discharge device the 70 jt d advantages th f, may t be underspace between the anode and cathodeof which, t d by reference t t following description is connected inshunt with the series connected t k i connection ith taccompanyingflrawreactor 9 and source 8. Signal currents produced ing inwhich Fig. 1 represents one emiiodiment in the microphone, in any Otherab e Big- 20 of my invention, and Fig. 2 represents a'modifihal device11, may be pp to e g id of the 75 cation thereof. device 10 through anamplifier l2. Normally Referring to Fig. 1 of the drawing I have shownthe grid of the device 19 is biased negatively by at 1 an electrondischarge device comprising a means of a source of potential 13 to adegree such pair of oppositely disposed anodes 2 and 3 which that themagnitude of Current fl w g in the '25 are arranged insubstantiallycylindrical formaanode circuit P e the rmal anode dissition about afilamentary cathode 4. Connected patioll f the discharge device. W Sgnal between the anodes is an inductance 5 and, if de- Currents are pp tthe id of device sired, a capacity 6 forming an oscillatory circuit.thiS grid becomes less negative, positive, th This oscillatory circuitalso includes of course the respect to the Cathode and the p d ce beaninherent capacity between anodes 2 and 3. Where tween the Cathode andanode is thereby reduced.

the system is to be used for the producti of Hence an increase incurrent from the source 8 ultra high frequency oscillations the externalcathrough reactor 9 d the p ce betweenthe paeity 6 d o tr t d indu ta 5may h anode and cathode of device 10 will occur. This removed, theinherent capacity betw th change in current in the anode of the device10 anodes and the inductance of the anode leads induces a Voltage inleaetel Which iS pp comprising the entire oscillatory circuit. The tothat of the source 8 and which causes a cathode 4 is heated by means ofan energy source diminution of potential on the anodes and a cor- 7, andthe anodes are supplied with energy fro responding increase in theintensity of oscillaa direct current source 8 through a reactor 9 tionsproduced. When the potential on the grid 40 which is connected to themid-point on the inof device 10 changes in the opp ect o ductance 5. thevoltage induced in reactor 9 aids that of Encircling the dischargedevice 1 is a coil 16 source 7 and causes a corresponding decrease inwhich is energized from a source of unidirectional the intensity ofoscillations produced. In this electromotive force 17 having a valuesuch that Way the oscillations produced may be ehiciently theoscillations produced in the ir it 5, 6 are of modulated in intensity inaccordance with the 100 desired intensity. By this means a magneticfield signals produced by the device 11. is produced between the anodes2 and 3 the lines In the modification of my invention shown in of forceof which extend parallel with the axis Fig. 2 the oscillatory circuit 5,6, is in the form of the cylinder formed by the anodes and hence of aseries resonant circuit connected between parallel with the cathode. oneof the anodes and the cathode. Also in this 105 It has been found thatthe amplitude of oscilfigurethe two anodes are maintained at differentlations produced by a generator of the type indipotentials, thepotential on the anode 3 being cated vary directly with the intensity ofthe maghigher than the normal potential on the anode netic field asindicated in copending application 2, this potential being supplied bymeans of a I of Elmer D. McArthur, Serial No. 320,709, filed source 15connected between the anode 3 and the n cathode. The potential on theanode 2 is supplied by a source 15 connected between the cathode and theanode 2 through the reactor 9. It has been found that, with a fixedvalue of potential of the source 14, and with the field current suitablyadjusted, that for a certain range of voltages on anode 2 less than thaton anode 3 the discharge device has negative resistance between thecathode and the anode 2, that is, as the potential of the anodeincreases the current flowing between the cathode and the anodedecreases. If the oscillatory circuit 5, 6 be connected between theanode 2 and the cathode and the potential on anode 2 is adjusted withinthe negative resistance range it will be found that oscillations areproduced in this circuit. These oscillations may be modulated in themanner described in connection with Fig. 1, the anode cathode circuit ofdischarge device 10 being connected in shunt with the reactor 9 andsource 15.

The load circuit upon the oscillation generator may be coupled to theoscillatory circuit by any form of coupling well known in the artalthough as shown in the drawing an inductive coupling represented bytransformer 5, 18 is employed.

While I have shown but a particular means for modulating theoscillations it will of course be understood that I do not wish to belimited thereto since other means may be employed for accomplishing thepurpose as, for example, that of varying the field current by means of amicrophone connected in that circuit.

While I have shown particular embodiments of my invention, it will ofcourse be understood that I do not wish to be limited thereto since manymodifications, both in the circuit arrangement and in theinstrumentalities employed, may be made without departing from thespirit and scope of my invention, as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, an electron discharge device comprising a pair ofoppositely disposed anodes, a cathode extending between said anodes,means for producing a magnetic field between said anodes, a resonantcircuit connected to said cathode and to at least one of said anodes,means for supplying potential to said anodes whereby oscillations areproduced in said resonant circuit having a frequency determined by thecharacteristics of said resonant circuit, said magnetic field betweensaid anodes being maintained constant during the production of saidoscillations, a source of continuously variable signal current, andmeans for modulating the amplitudes of oscillations of said frequency inaccordance with the continuous variations in said signal current.

2. In combination, an electron discharge device having a pair ofoppositely disposed anodes, a cathode extending between said anodes, aresonant circuit connected between said anodes, means for producing amagnetic field between said anodes, means for impressing positivepotential on said anodes, a source of continuously variable signalcurrent, and means connected between the anodes and cathode formodulating the oscillations produced in accordance with the continuousvariations in said signal current.

3. In combination, an electron discharge device comprising a pair ofoppositely disposed plate members, a cathode extending between saidmembers, means for producing a magnetic field between said plate membersand parallel with said cathode, a resonant circuit including thecapacity between said plate members, means for supplying unidirectionalpotential to said plate members having value such that oscillations areproduced in said resonant circuit, a source of continuously variablesignal current, and means for varying said potential in accordance withthe continuous variations in said signal current thereby to modulate theoscillations produced.

4. In combination, an electron discharge device, comprising a pair ofoppositely disposed anodes, a cathode extending between said anodes,means for producing a magnetic field between said anodes, an oscillatorycircuit comprising the inherent capacity existing between said anodesand an inductance connected between said anodes, a reactor connectedbetween a point on said inductance and said cathode, means for supplyingpotential through said reactor to said anodes such that oscillations areproduced in said oscillatory circuit, and means for varying thepotential on said reactor in accordance with desired signals thereby tomodulate the oscillations produced.

5. In combination, an electron discharge device, comprising a pair ofoppositely disposed anodes, a cathode extending between said anodes,means for producing a magnetic field between said anodes, an oscillatorycircuit comprising the inherent capacity existing between said anodesand an inductance connected between said anodes, a source ofunidirectional potential and a reactor connected in series between apoint on said inductance and said cathode, said potential being of valuesuch that oscillations are produced in said oscillatory circuit, anelectron discharge path connected in shunt with said series connectedsource and reactor, and means for varying the impedance of said path inaccordance with desired signals thereby to modulate the oscillationsproduced.

6. In combination, an electron discharge device comprising a pair ofoppositely disposed anode members, an electron emitting cathodeextending between said members, means for supplying positive potentialto both of said anode members, means for producing a magnetic fieldbetween said anodes, an oscillatory circuit connected to the cathode andto one of said anodes, the potential on said anodes being such thatsustained oscillations are produced in said oscillatory circuit, andadditional means connected across a portion of said oscillatory circuitto modulate the oscillations produced.

7. An oscillation generator comprising an hermetically sealed containerwherein are contained an electron emitting cathode and a plurality ofanodes, means for subjecting electrons flowing from said cathode to saidanodes to a magnetic field, a tunable circuit connected to said anodes,a source of potential for polarizing saidanodes with unidirectionalpotential, and means for varying the potential applied to the anodes inorder to modulate the oscillations generated in IMO

